Technical Field
This application relates to pressure sensors, including pressure sensors that expose a flexible diaphragm to gas or liquid having a pressure to be measured.
Description of Related Art
Pressure sensors that utilize a flexible diaphragm may be used in a wide variety of applications. One side of the flexible diaphragm may be exposed to gas or liquid having the pressure to be measured. The other side may be isolated from the gas or liquid, but be exposed to a sealed chamber. Changes in the pressure to be measured may cause corresponding changes in the flexure of the flexible diaphragm. Measurement of these changes can serve as indications of the pressure changes.
Some pressure sensors are used in environments that can damage the flexible diaphragm. For example, some pressure sensors are used in chemical vapor deposition (CVD) systems. These systems can cause a steady buildup of sediment on the flexible diaphragm and/or changes in the flexible diaphragm due to atomic doping. This damage to the flexible diaphragm can adversely affect the accuracy of pressure measurements that are made.
One approach to dealing with this problem may be to periodically replace the flexible diaphragm. However, this can result in both premature and unduly delayed replacements and lost use of the system during the replacement process.
Another approach may be to perform periodic calibration tests on the flexible diaphragm. Again, however, the system may need to be taken off-line and hence temporarily removed from use.